Well head seal with means to limit compression of the seal



June 12, 1962 E. F. CQQKE, JR 3,038,745

WELL HEAD SEAL WITH MEANS TO LIMIT COMPRESSION OF THE SEAL Filed May 2,1957 EDWARD F- COOKE, JR

INVEN TOR.

ATTORNEY United States Filed May 2, 1957, Ser. No. 656,722 1 Claim. (Cl.285148) This invention relates to well head seal assemblies andparticularly to casing hangers and sealing means for such assemblies.

The principal object of the invention is to provide a novel apparatusfor suspending and sealing a casing in a well head assembly.

Another object is to provide such apparatus which operates in such amanner that casing deflection is reduced to a minimum therebyeliminating bottlenecking.

Another object is to provide such apparatus which includes casing slipsand a distortable seal arranged in such a manner that sealing isautomatically effected when the hanger is positioned around a casing andthe weight of the casing released.

Another object is to provide a slip bowl which in addition to supportingthe casing slips forms part of the means for sealing the casing withinthe casing head.

Still another object is to provide a casing suspension and seal devicewhich can be introduced through blowout preventer equipment or the liketo a position in a well head to support the casing and provide a sealwith the casing head.

A further object is to provide a casing hanger and seal assembly, thearrangement of the combination being such that the weight of the casingis used in a controlled manner to tighten the seal.

A still further object of the present invention is to provide a casinghanger and seal having a slip bowl and easing slips arranged therein tocompress gasket means into sealed position between the casing head andthe inner casing, the arrangement being such that the weight of theinner casing is used to compress the gasket.

Other and further objects of the present invention will be apparent fromthe following description, the accompanying drawing, and the appendedclaims.

In the drawing, there is shown in vertical cross section a casing headhaving a hanger assembly disposed therein to support an inner casing.The left half of the drawing shows the assembly before the release ofthe casing with no pressure applied to the packing; the right half ofthe drawing shows the assembly in supporting position with the casingreleased and the seal compressed.

Referring now to the drawing, casing head 10, which has a flange 11 forsecurement to suitable fittings (not shown), is formed with an axialbore 12and a downwardly and inwardly tapered shoulder 13. Arranged inthe casing head is a slip bowl 14 having a main cylindrical body fittinginto bore 12 and a peripheral tapered portion or seat 15 provided withteeth 16 for engagement with casing head shoulder 13. Slip bowl 14,which consists of a plurality of segments, has at its upper end aninwardly directed flange 17 through which extend axial holes 18. Ahorizontal shoulder 19 is provided on the inner side of the slip bowl toprovide a seat for easing slips 20 as later more fully described. Slips20 are each atent C formed with a radial flange 21 having threaded holes22 therein. The inner wall of each of the slips is toothed forengagement with casing 23.

The seal assembly of of the hanger includes a retaining ring 2.4positioned on bowl flange 17, a compressible annular packing element orseal 25, a compression ring 26, and a plurality of bolts 27, the headsof which abut compression ring 26. The bolts pass through the annularseal and are screwed into holes 22 in the slip flanges.

In operation, the hanger is mounted around the casing 23 and loweredthrough blow out preventers and valves into the well head body. Theweight of the hanger, when the slip bowl 14 contacts the bore shoulder13, causes the segments of the slip bowl 14 to move inwardly forcing theslips into engagement with the casing 23. The weight of the casing thencauses the slips to move downward. A downward pull on the support-ingbolts and compression ring as results and the packing 25 is com pressedand forced radially outward against the bore 12 and radially inwardagainst the casing 23. This action continues until the load issufficient to cause the bowl teeth 16 to bite into shoulder 13 thuspreventing further movement of the slip bowl segments. Thus the slipbowl is prevented from further wedging action against the slips. In manycases it has been found that such further wedging action causesbottlenecking of the casing wall. Downward movement of the slips 2% willcontinue, however, to cause further compressive forces to be applied tothe packing. Such continued movement of the slips will be stopped whenflange 21 engages shoulder 19 of the slip bowl. This results in thepacking 25 being loaded to efiect a pressure seal and so limits the loadapplied to the bolts and packing as the additional load on the slips istransferred to the slip bowl.

While there has been hereinbefore described an approved embodiment ofthis invention, it will be understood that many and various changes andmodifications in form, arrangement of parts and details of constructionthereof may be made without departing from the spirit of the invention,and that all such changes and modifications as fall within the scope ofthe appended claim are contemplated as a part of this invention.

What I claim is:

A well casing hanger and sealing assembly comprising a slip bowl adaptedto be received by a casing head, said head having an inwardly taperedseat with a cylindrical bore thereabove, the upper portion of the slipbowl being cylindrical and of a dimension to substantially fill thespace between a well casing inserted into said head and said casinghead, said bowl providing a. seating surface at its upper extremity,said bowl including a plurality of segments circumferentially spacedapart a predetermined distance; each segment being tapered on its outerlower face complementary to said tapered seat; a toothed portion on saidcomplementary tapers adapted to engage said tapered seat to limitmovement of the bowl; a radial shoulder on the inner periphery of saidbowl; a seal assembly on said seating surface, said assembly including acompression ring spaced axially from said seating surface and a packingring therebetween; a plurality of slip segments within said bowl eachhaving a radial shoulder thereon above said bowl shoulder, said radialshoulder on the slip segments being normally spaced axially from saidbowl shoulder a distance less than the axial thickness aoeams of theuncompressed packing ring; well casing engaging means on the slipsegments; substantially axially straight cooperable surfaces on the bowland slips below said radial shoulders adapted upon abutment to forcesaid slips radially inward into gripping engagement with the pipe, saidinward movement limited by said toothed portion on said bowl moving intogripping engagement with said tapered seat, and said radial shoulderscooperating to prevent over compression of said packing ring; andconnection means between the compression ring and the slip segments,said connection means serving to force the compression ring toward theslip bowl to expand the packing ring inwardly and outwardly into sealingengagement with the well casing and casing head.

UNITED STATES PATENTS Adair Mar. 15, 1932 Nixon May 3, 1932 Black Aug.16, 1932 Gordy Jan. 17, 1939 Penick Aug. 26, 1947 Allen May 22, 1951Mueller Jan. 6, 1953 Allen July 6, 1954 Jones Sept. 14, 1954 Rhodes Feb.25, 1958 Johnson May 26, 1959 Allen Jan. 12, 1960

